CD has questions related to colour differences in the sexes of butterflies, especially in relation to HWB’s paper ["On variation in sexes of Argynnis diana", Proc. Entomol. Soc. Philadelphia 4 (1865): 204–7].

Mentions that his MS on Lepidoptera [for Descent] is longer than he intended and the information is four-fifths owed to HWB.

Thanks HWB for answering questions.

The MS on Lepidoptera is almost finished and he is glad HWB will read it; he is fearful of mistakes, not being familiar with the subject.